This application relates to a refrigerant system having a reheat function utilizing variable speed drives as a source of heat.
Refrigerant systems are utilized in applications to change the temperature and humidity or otherwise condition the environment. In a conventional refrigerant system, a compressor delivers a compressed refrigerant to a heat exchanger, known as a condenser, which is typically located outdoors. From the condenser, the refrigerant passes through an expansion device, and then to an indoor heat exchanger known as an evaporator. In the evaporator, moisture may be removed from the air, and the temperature of air blown over the evaporator coil is reduced. From the evaporator, the refrigerant returns to the compressor. Of course, basic refrigerant systems are utilized in combination with many other optional features and in various design configurations.
In some cases, while the system is operating in a cooling mode, the temperature level of the indoor air stream to provide a comfort environment in a conditioned space may need to be higher than the temperature that would provide the ideal humidity level. On the other hand, lower the temperature of the air stream more moisture can be removed from the air. These contradicting trends presented challenges to refrigerant system designers. One way to address such challenges is to utilize various schematics incorporating reheat coils. In many cases, a reheat coil placed in the way of an indoor air stream downstream of the evaporator is employed for the purposes of reheating the air supplied to the conditioned space after it has been cooled in the evaporator, and where the moisture has been removed.
Known reheat systems require additional heat exchangers, flow control devices, piping, etc. Of course, it is typically beneficial to reduce a number of components, decrease refrigerant cycle and control logic complexity and consequently improve system reliability.
Variable speed drives that include dedicated inverters and power/control electronics are being incorporate more often into refrigerant systems. The inverters and power/control electronics generate heat that needs to be removed to improve efficiency and reliability of the electrical hardware. This wasted heat can be selectively utilized to improve comfort in the conditioned space